Improving assessments of coastal ecosystems – Adjusting coastal fish indicators to variation in ambient environmental factors

The application of ecological indictors for assessing the environmental status of ecosystems play an important role for effective management. However, natural variability may limit the indicators’ ability to provide relevant information about anthropogenic pressures and guide management action. Coastal fish species are not only a resource for commercial and recreational fisheries but also key ecosystem components in the Baltic Sea, and is therefore used as management objectives within the EU Marine Strategy Framework Directive and the HELCOM Baltic Sea Action Plan. A challenge, however, is that the distribution and abundance of coastal fish populations in Baltic Sea is also influenced by spatial and temporal variation in ambient environmental factors. Here, using 16 years of monitoring data, over a latitudinal range of 56 – 66°N along the Swedish Baltic Sea coast, we evaluated the effect of variability in water temperature and depth, and wave exposure for three indicators of environmental status assessment in the Baltic Sea: Abundance of perch, Abundance of Cyprinids, and Abundance of Piscivores. Generalized linear mixed models (GLMM) revealed an overall positive linear relationship between water temperature for all indicators, and overall negative linear relationships to depth and wave exposure. When adjusting indicator values using the parameter estimates from the GLMM models, the variability and 95 % confidence interval for all three indicators were reduced. The adjustment, however, did not have a strong impact on the assessment of the ecological state of the indicator. Our results suggest that adjusting coastal fish indicators to variation in local ambient environmental factors will increase their precision, and hence, the confidence in the assessment of environmental status

Improving assessments of coastal ecosystems – Adjusting coastal fish indicators to variation in ambient environmental factors

The application of ecological indictors for assessing the environmental status of ecosystems play an important role for effective management. However, natural variability may limit the indicators’ ability to provide relevant information about anthropogenic pressures and guide management action. Coastal fish species are not only a resource for commercial and recreational fisheries but also key ecosystem components in the Baltic Sea, and is therefore used as management objectives within the EU Marine Strategy Framework Directive and the HELCOM Baltic Sea Action Plan. A challenge, however, is that the distribution and abundance of coastal fish populations in Baltic Sea is also influenced by spatial and temporal variation in ambient environmental factors. Here, using 16 years of monitoring data, over a latitudinal range of 56 – 66°N along the Swedish Baltic Sea coast, we evaluated the effect of variability in water temperature and depth, and wave exposure for three indicators of environmental status assessment in the Baltic Sea: Abundance of perch, Abundance of Cyprinids, and Abundance of Piscivores. Generalized linear mixed models (GLMM) revealed an overall positive linear relationship between water temperature for all indicators, and overall negative linear relationships to depth and wave exposure. When adjusting indicator values using the parameter estimates from the GLMM models, the variability and 95 % confidence interval for all three indicators were reduced. The adjustment, however, did not have a strong impact on the assessment of the ecological state of the indicator. Our results suggest that adjusting coastal fish indicators to variation in local ambient environmental factors will increase their precision, and hence, the confidence in the assessment of environmental status

Demands on monitoring

This chapter provides a short overview of the types of processes for reporting as well as legislation that governs why and how monitoring is undertaken and some of the ways in which stakeholders are involved at different levels. Because monitoring for the policy side is, by default, mandated monitoring, this type becomes the focus of this chapter, while noting that many policies and legislation may have been prompted by the results of question-driven monitoring, pointing out areas of concern. In fact, the iterative process of monitoring, analysis, and reporting to a government that, in turn, changes the policies to better fit concerns or issues needing addressing can be seen as a co-development. Whereas the previous chapter illustrated what monitoring is, this chapter illustrates some of the demands on monitoring in legislation and policy, where they outline what monitoring is asked to contribute. The chapter reviews legislation on the global scene, on the community level of the European Union, and at national levels in the areas of water bodies and semi-aquatic, agricultural, urban, and forested semi-natural or natural landscapes

Kustfiskövervakning

Under sommaren 2002 genomfördes pilotförsök med den nya Nordiska metodiken för provfiske, parallellt med att ordinarie fiskövervakning med Kustöversiktsnät genomfördes. En jämförelse mellan de bägge metoderna visar att den Nordiska metodiken ger en bättre täckning av artförekomst inom ett undersökningsområde, vilket i sin tur ökar möjligheterna att observera förändringar av den biologiska mångfalden. Även ett bredare storleksspektrum av fisk fångas, vilket ger en mer sann bild av hela fisksamhällets och enskilda bestånds storleksstruktur. Storleks- och åldersstrukturen kan i sin tur spegla effekter av omgivningspåverkan som t.ex. rekryteringsstörningar eller överfiske. Att även de minsta storleksklasserna fångas medger att säkrare beståndsprognoser kan göras, och att fiskrekryteringsstörningar observeras i ett tidigare skede